Electrical rectifying system



STEM

www C J l TEFYING Patented Feb. 26, 1929.

JULIUS JONAS, `OF BADEN, SWITZERLA BROWN BOVERI & CIE., 0F BADEN,SWITZERLAND.4

ND, ASSIGNOB T0 AKTIENGESELLSCHAFT SWITZERLAND, 'A JoINT-s'roox coMPANYor ELECTRICAL RECTIFYINGSYSTEM.

Application led January 26, 1927, Serial No. 163,611, and in, GermanyJanuary 28, 1926.

This invention `relates to apparatus for the rectification ofalternating electr-leal current-s to direct current and has particularapplicability in systems in which rectiiers of the mercury vapor typeare employed.

The general object of the invention 1s the provision of an effectivemeans for obtaining a distribution of the impressed load, in a desiredconstant ratio, between rectitiers operating in parallel and fed fromseparate secondary windings of a single transformer. Another object isthe improvement of the power -factor in' apparatus of this-type.

Other and further objects will be polnted out or indicatedy hereinafteror Will be apparent to one skilled in .the art upon an understanding ofthe invention or its employment inpractice.

Y In the accompanying drawing forming a part of this specification, Iillustrate in diagrammatic fashion certain structural arrangementsinwhich the invention may be embodied or availed of, but it is to beunderstood that these are presented for purpose of illustration andexample only, and are not to be accorded any interpretation having theeffect of limiting the appended claims short of the true and mostcomprehensive scope of the invention in the art.

Insaid drawing,

Fig. 1 is a diagram of rectifying apparatus comprising two mercury vaporrectfiers arranged for operation in parallel and fed from a single phasetransformer;

Fig. 2 is a diagram representative of a longitudinal section through thecore and windings of a transformer having two secondary windingsarranged in a distributed relationship such as to obtain a definitedistribution of the load betwben them; and Fig. 3 is a similar diagramof a transformer portion having four secondary windinfrs..

tWhen a plurality of rectiiers are'y sup plied from a singletransformer, care must be taken in the arrangement of the windings ofthe latter to insure proper distribution of the load among the severalrectifiers during parallel o eration. The result may be accomplishedformer al separate secondary for each reetiier and arranging thesections of said secondary windings which carry currents of y providingon the trans.

the same phase simultaneously, on the appropriate core of a transformer,opposite the primary winding. If the secondary windings are arrangedwithout subdivision von the primary winding, the primary ampere-turnswill be* fully compensated only at times when the distribution of 'theload between the rectitiers isin normal proportion. By the presentinvention,

provide an arrangement whereby, in the event of a change of' the loadconditions as between the rectifiers, the manner in which thetransformer windings areoinductively coupled will give rise to E. M. F.sopposing a change in the load distribution between the rectiliers. Thearrangement of the secondary windings is suitable not only fordistribution of t-he load among different rectiliers, but also'xl forcases where parallel operating anodes are to be supplied whetherbelonging to different or the same rectiiers. This arrangement of thewindings is characterized in the first place by a side by sidearrangement of the different secondary windlngs in subdivisions whichare distributed over the primary winding. Fig. 1 shows, by way ofexample, a. transformer having a primary winding A and four secondarywindings B, C, D and E for, supplying the rectiiers 10 and 11. Theanodes a of rectifier 10 are supplied by the secondary windingsjll andC, while the anodes a of recti tier 11 are supplied by secondarywindings D and E. Disregarding the magnetizing current, and starting onthe assumption thatthe current in the primary induces, at

side by side every point on the wound core, a current 1n the secondaryof such magnitude that the. ampere-turns per unit of core lengthbalance, it follows rent tends to maintain a value corresponding to theratio of am ere-turns per unit of core length.v \Hence, y providing allthe adjacent vsecondaries with the same number of turns, which isessentiall for parallel operation since they must have the same voltage,with a given load Vcurrent in the primary, the current in each secondarywindy ing ecomes 'a function of its turns per unit of corev length, thelower values of the latter corresponding to larger currents. obtain anydesired distribution Y among the parallel rectiliers or anodes, inaccordance with the present invention,\the

that the secondary eur-.

arrangedl side by side,

ratio desired.

.ary windings B, C, D and secondary windings, in 'addition to being mustbe so proportioned that the ratio of their turns per unit of core lengthis the reciprocal of the load By way of illustration, ifthe secondaryWinding D contains the same number of turns as the secondary winding B,but is distributed v overa core length twice that embraced by winding B,the voltage of the two windings will be the same, but the current in Dwill be twice that in B. The proper compensation of the primary windingis attained by the proper proportioning of the secondary windings andtheir distribution over the primary winding in appropriate subdivisionsarranged side by side in proper linkage association with the primarywinding. An example of such arrangement is illustrated in Fig. 2 whereinthe secondary winding D `is arranged in the subdivisions D1, D2, D3, D*and D5 which embrace, in the aggregate, twice the core length embracedby the aggregate subdivisions B1, B2, B3; B4 and B5 of the winding B.Thus, in the ment here illustrated, the winding D will take twice theload of the winding B. Fig. 3 illustrates an arrangement of the second-E in a sandwich re ationship with the primary winding A. Here theprimary windingis arrangedin the sections A1, A2, A3 and A4, thesecondary winding B in the sections B1 and B2, the secondary winding Din the sections D1 land D2, the secondar winding C in the sections C1and G2 and t e secondary winding E in the sections E1 and E2. With each"of the windingsr D and E embracing twice the core length embraced byeach of the windings B and C, it follows that each of the windings D andE will carry a load twice ythat carried by each of windings B and C.

With the similar secondaries connected to the same rectifier, therefore,as illustrated in Fig. l, the rectifier fed by windings D and E willtake a load twice that taken by the rectifier supplied by windings Bland C, While the voltage impressed'on the rectifiers will be the same.To contribute to equalization of the voltage drops in the differentsecondaiy windings, Atheir subdivisions are arrange alternately 'in sucha wayVY that sections belonging to the different secondaries succeedeach other in turn along the core.

What I claim is:

1. In electric current rectifying apparatus, the combination with aplurality of rectifier terminals for operation in parallel, of atransformer for feeding said terminals, said transformerv having aplurality of secondary number of turns and arranged in like couplingrelationship to the core, respective secondary windings embracingdi'erent lengths arrangewindings each containing `the sainel ingapparatus of core which are in proportion to the desired loaddistribution between the secondary windings, the secondary windings ofdifferent core length being connected to different rectifier terminals.

i 2. In electric current rectifying apparatus, the combination withrectitiers arranged for operation in parallel, of a transformer fordistributing the load between the rectifiers, said transformer' havingdifferent secondary windings of equal voltage connected to differentrectiiiers, said secondary windings arranged side by side on thetransformer core and having the ratio of their turns per unit of corelength, one to another, equal to the reciprocal of the ratio of thedesired load distribution between the rectifiers.

3. A load distributing device for rectiiers operating in parallel,comprising a transformer having different secondary windings connectedto diderent rectifiers, said secondary windings having like voltagedetermining characteristics and having the ratio of their'turns per unitof core length inversely proportional to load distribution betweentherectiliers.

4. A load distributing device for rectifiers operating -in parallel,comprising a transformer having different secondaryy windings connectedto diiferent rectiiers, the secondary windings being distributed alongthe core in subdivisions with the subdivisions of the different windingsarranged side by side in successive order alongthe core, the ratio ofturns of the different windings per unit of core length.-being inverselyproportional to the desired ratio of load distribution between therectifiers. Y

5. A load distributing device for rectifiers operating in parallel,comprising a transformer having its, primary winding distributed alongthe core and different vsecondary windings for connection to differentrectitiers, said secondary windings being arranged in subdivisions withthe subdivisions of different windings disposed side by side insuccessive order along the core, the -ratio l of turns of the differentsecondary windings per unit of core length being inversely proportionalto the desired ratio of load distribution between theditferentrectifiers."

the ratio of desired f 6. The combinationV with a plurality of irectifier anodes arranged for parallel operation, of a transformerhaving different secondary windings connected to different anodes, saidAsecondary windings arranged in subdivisions side by side alternatelyalong the core, and the ratio of the turns of the different windings perunit of core length bein linversely proportional to the ratio of theesired load distribution between the different anodes. y l v f 'L Inacurrent-rectifying system, rectifyhaving .c parallel-connected anodessubject to different load conditions; and a single supply transformerfor said apparatus comprising a first and a second set of secondarywindings connected respect tively to said anodes, a core common to saidwindings, and primary winding means disposed about sai core in fixedand` permanent relation with respect thereto, the number of turns of thesecondary windings comprising the first set being vsubsta-ntiall equalto the number of turns of the secon ary windings comprising the secondset, the distribution with respect to said `core windings`4 comprisinthe first set being unequal to such distri ution ofthe secondary 15windings comprising the second set in amount inversely proportional tothe load conditions of the respective anodes connected tosaid sets ofwindings.

In testimony whereof I have hereunto sub- 20 scribed my name this 5thday of January A. D. 1927 at Zurich, Switzerland.

JULIUS JONAS.

of the secondary

